Can a boyfriend be accused for not marrying a girl?

Hello, Me and my boyfriend are in relationship from past 7 years. Due to unfortunate incident we were not speaking for a span of 1 year. In this time, a common friend of us got into physical relationship with him. Neither of them proposed nor promised tat they both will get married. But she got pregnant and they aborted baby. At that time my boyfriend promised her if they ask for marriage certificate for abortion he will marry her. Even after 1 year still she texts him and blackmails him daily that she will commit suicide if he doesn't marry her. Recently she got to know that we both are back together. She s blackmailing him again stating she will lodge a complaint with all documents of abortion. I'm not demeaning a girl just for my boyfriend. She already had physical relationship with few others as well and was trying to trap people. 1)she has whats app texts of my boyfriend promising to marry her if the abortion doesn't happen. 2)we don't have any proof with whom she was physical earlier. 3)what action can be taken if she lodges a complaint. Can I save my boyfriend from her? 4)In her whats app texts she has clearly mentioned that they have broken up with each others consent 5)She has asked him if he s okay to marry after break up. But he has never said Yes for her proposals. 6)she only initiated sexting all the time which has been ignored by my boyfriend. 7)she is not letting any girl to come into my boyfriend's life Please suggest what legal actions can be taken for this? Thanks, V